Transformer.



No. 764,485. PATENTED JULY 5, 1904.

W. S. MOODY.

TRANSFORMER.

APPLICATION FILED DEC. 14, 1903.

NO MODEL.

Fig. 2.

UNITED STATES Patented July 5, 1904.

PATENT OEEicE.

l/VALTER S. MOODY, OF SOHENEOTADY, NEIV YORK, ASSIGNOR TO GEN- ERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

TRANSFORMER.

SPECIFICATION forming part of Letters Patent No. 764,485, dated July 5,1904.

Application filed December 14, 1903. Serial No. 185,008. (No model.)

To all whom it may concern.-

Be it known that I, WALTER S. MOODY, a citizen of the United States,residing at Schenectad y, in the county of Schenectady and State of NewYork, have invented certain new and useful Improvements in Transformers,of which the following is a specification.

In designing long electric transmission systems it is now a commonpractice to provide transformers arranged so as to utilize when they arefirst installed as high a voltage as it is then thought safe to use, butnot so high as may ultimately be found practicable. To accommodate thispractice, transformers are now built adapted for a maximum voltage ofsixty thousand volts, but arranged with taps, so that they may be usedfor forty thousand or fifty thousand volts. When operating at thereduced voltage, there is a considerable portion of the high-voltagewinding idle. Those coils of the low-voltage winding which are adjacentto the idle coils of the high-voltage winding, due to the increaseddistance between them and the active portion of the high-voltagewinding, set up quite a higher active flux about them. The reactancethus developed may be sufficient to increase the total reactance of thetransformer by twenty-five per cent. or more, and is thus highlyobjectionable if good regulation be one of the objects sought for in thedesign of the transformer. If, however, the low-voltage coils are eachwound for the full voltage and areconneoted in multiple, this increaseof reactance will not occur, since those coils adjacent the idlehigh-voltage coils will then only take a small current instead of beingtraversed by the total current, as would I be the case were they all inseries. That portion of the total current which the idle lowvoltagecoils would take were all the highvoltage coils in use is under thesecircumstances defiected to low-voltage coils near the activehigh-voltage coils.

The novel features characteristic of the invention described brieflyabove are set forth with particularity in the appended claims. Theinvention itself, however, may perhaps be better understood by referenceto the accompanying drawings, in which Figure 1 is a diagram of the oldmethod of connecting the subdivided windings of a transformer, and Fig.2 is a diagram representing my improved method of arranging windings ofthe transformer.

In Fig. 1 the high-voltage winding of the transformer consists of anydesired number of coils or sections, such as at l to 6, inclusive. Thesecoils are all connected in series. The low-voltage winding consists,similarly, of any suitable number of coils 7 to 12, inclusive, connectedin series with each other. Where the maximum voltage is for any reasonnot used on the high-voltage winding, a corresponding amount of thewinding is left out of circuit in order to raise the ratio oftransformation of the transformer, and thus preserve the same voltageupon the low-voltage winding as would be given by the winding if thefull voltage were used with the total high-voltage winding. WVith lowerthan the full voltage some of the high-voltage coils are left out ofcircuit as, for example, the coils 1 and 6in which case the leads 13 and14 are connected to the outside terminals of the coils 2 and 5. WViththis arrangement it is evident that the low-voltage coils 7 and 12,opposite the idle high-voltage coils 1 and 6, carry the full low-voltagecurrent and being more distant from the active high-voltage coils thanare the other coils 8 to 11, inclusive, setup a higher reactive orleakage flux. The additional reactance which is thus produced when partof the high-voltage coils are unused is thus decidedly objectionable. Toovercome this objection, the low-voltage winding may consist of a numberof coils or sections, as 15 to 20, inclusive, Fig. 2, each wound for thefull value of the voltage of the low-voltage side of the transformer.These coils are all connected in multiple with each other, as indicated,and transmit current through the mains 21 and 22. As before,-thehigh-voltage winding of the transformer is the same as that shown inFig. 1. hen now the transformer shown in Fig. 2 is in operation, thelow-voltage coils 16 to 19, inclusive, carry most of the current. Theoutside coils 15 and 20, because of their higher reactance, carry muchless than their selves be subdivided.

proper share of the load. This, however, is not objectionable.

In the foregoing description it is to be understood that thetransformer, so far as my invention is concerned, may be operated witheither winding as a primary and the other as a secondary. Furthermore,it is to be understood that the coils or sections 15 to 20 may them-Thus the coil or section 15 may consist of individual coilsinterconnected with each other in series or multiple or in any otherdesired manner, When, therefore, I speak of coils, I mean either asingle winding or a combination of windings. What I claim as new, anddesire to secure by Letters Patent of the United States, is-

1. In a transformer, the combination of two inductively-related windingseach made up of a plurality of coils, the coils of one winding beingconnected in series with each other and the coils of the other windingin'multiple with each other,'and connections for utilizing less than thewhole number of the series-connected coils.

